jemalloc_collect_global_profile_samples_in_trace_log
Store jemalloc’s sampled allocations in system.trace_logjemalloc_max_background_threads_num
Maximum amount of jemalloc background threads to create, set to 0 to use jemalloc’s default valuejemalloc_merge_tree_arenas
Number of dedicated jemalloc arenas for long-lived MergeTree per-part and per-table metadata.0 disables the dedicated arena (metadata uses the default per-CPU arenas). 1 uses a single shared arena. N > 1 creates a pool of N arenas and routes allocations per CPU; on many-core machines this avoids serializing metadata allocation on a single arena’s locks. Capped at the number of CPUs the process may run on (its affinity mask), so a large value (or the core count) yields one arena per allowed CPU. Applied at startup.
jemalloc_profiler_sampling_rate
Controls jemalloc’slg_prof_sample — the base-2 logarithm of the average interval (in bytes) between allocation samples.
The default value of 19 corresponds to 512 KiB. Setting it to a smaller value increases sampling frequency (more overhead, more detail), and a larger value decreases it.
Changing this value calls prof.reset which resets all accumulated profiling statistics. Requires profiling to be enabled (MALLOC_CONF=prof:true).